The present invention relates to a modular key-slot accessory mounting system for a firearm.
Firearms such as the AR15, M16, M4 are known to include a handguard mounted to the upper receiver and extending around a portion of the barrel. The handguard can be grasped by the operator. It is known to mount accessories such as flashlights, scopes, and handgrips to the handguard and for this purpose several mounting systems are well known in the industry.
One known accessory mounting system is disclosed in U.S. Pat. No. 8,925,236 to Mayberry et al. This system includes a handguard with slots having uniform width and a length between first and second ends. A T-nut of the accessory to be mounted to this system includes a major dimension and a minor dimension. The major dimension is wider than the width of the slot but shorter than the length of the slot and the minor dimension is not as wide as the width of the slot. To mount the accessory to the handguard, the T-nut is turned to align the major dimension with the length of the slot. After the head of the T-nut has been inserted into the slot and is clear, the T-nut is turned so the major dimension extends across (e.g., perpendicular to) the slot. The accessory is then slid in the slot until a recoil lug adjacent the T-nut engages the first end of the slot and another recoil lug engages the second end of the slot. The T-nut is then tightened to clamp the accessory to the handguard with the head of the T-nut extending across the elongated opening.
Another known system is illustrated in U.S. Pat. No. 9,377,274 to Kincel. This system includes a handguard with keyhole-shaped slots. Each keyhole-shaped slot (referred to as a “void 210” in the patent) has a circular entry aperture (“first region 215”) and an elongated opening (“second region 220”) extending away from the entry aperture to a distal end. An accessory to be mounted to this system includes fastener (“coupling member 225”) including a head that passes through the entry aperture but is wider than the elongated opening. To mount the accessory this system, the heads of first and second fasteners are inserted into the entry apertures of adjacent keyhole-shaped slots and slide into the elongated openings. The fasteners are then tightened to clamp the accessory to the handguard with the head of the fasteners T-nut extending across the elongated opening.